1. Field of the Invention
This invention relates to a process for making image sensor packages and more specifically to a singulation method used in the image sensor packaging process.
2. Description of the Related Art
Image sensors are increasingly in demand for incorporation into electronic devices. They may be used for a variety of applications including consumer electronics like digital cameras, cellular telephones and hand-held scanners.
In order to protect the image sensors in the form of an integrated circuit die, i.e., the image sensor chip, from physical damage and from contaminants in the surrounding environment, it is the practice to place the image sensor chip in a package. The package typically includes an opening sealed by a transparent lid to allow light or other forms of electromagnetic radiation to pass through to sensing circuitry on the active surface of the image sensor chip. Another purpose of the package is to provide electrical communication with other components of the larger electronic device into which they are incorporated.
The image sensor chips are typically packaged into an array of many individual units on a substrate to meet large-scale production requirements. Then, a punching operation is conducted to separate out the individual units. However, such a punching operation requires a substrate having a low-density unit designs which significantly increases the manufacturing cost because the substrate accounts for up to 60% of the total assembly cost. In addition, the biggest drawback of such a punching operation is that every different shape or size of packages requires a dedicated punching tool, e.g., if the shape or the size is altered, the punching tool must be redesigned. The development and manufacture of a punching tool typically takes about 3˜4 months thereby significantly increasing assembly lead time. This is unacceptable since current image sensor packages have very short lifetimes (typically about 3˜6 months).